JPS61255652A - Production of denture bed having elastic lining material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a method for manufacturing a denture base having an elastic lining material.

<Conventional technology> Conventionally, denture bases have been provided with rubber elastic or flexible lining materials in order to provide stable and firm support to the alveolar ridge, thereby preventing wobbling during mastication, involuntary tenderness, and loss of dentures. It is known that it is formed on the alveolar ridge-adhering surface of the main body. Materials for such lining materials include those using soft fluororesin (Japanese Patent Application Laid-Open No. 55-21919), collagen (Japanese Patent Publication No. 57-50498), and silicone rubber (Japanese Patent Application Laid-open No. 57-50498). 58-54946), natural rubber,
Those using isoprene polymer (Japanese Patent Application Laid-open No. 55-269
No. 23), and one using a styrene-butadiene thermoplastic elastomer (Utility Model Application No. 58-101622).

<Problems to be Solved by the Invention> When the above-mentioned materials are used as the lining material, the following problems arise.

(2) In the case of soft resin, its rubber elasticity is limited, making it unsuitable for maintaining axotiment, and when it is deformed by local pressing force, it does not have the same restoring force as rubber.

■If a thin sheet is pressed against the mucosal surface of the denture base, it is difficult to fill the undercut portion of the retaining tooth, and sufficient retaining force cannot be obtained.

■Since silicone rubber is a vulcanized rubber, it is difficult to modify it once it has been vulcanized and molded.

The present invention was made in view of these circumstances, and uses a new thermoplastic elastomer as the lining material.
By synthesizing the optimal adhesive for this lining material,
The purpose of the present invention is to realize a method for manufacturing a denture base that does not require special machinery and is easy to mold.

Means to solve problems〉 The method for manufacturing a denture base according to the present invention includes the following steps.

The step of forming a spacer with a shape matching the lining material on the plaster jaw model in the first flask, mounding up the wax in the shape of the denture base body on the spacer, and arranging the artificial teeth on the wax; A step of stacking a second flask on a first flask and filling and solidifying gypsum in a fluid state;
Step of dividing the above pair of flasks and removing only the above wax; PMMA powder is placed between the above first flask or a third flask having the same jaw model and the above second flask with liquid methyl methacrylate ( Below MM
(referred to as A) A step of sandwiching the mochi-like PMMA obtained by kneading it with the monomer, heating it, pressing it, and polymerizing it; dividing the above pair of flasks and adding at least a predetermined exposed surface of the denture base main body formed by polymerizing and hardening the above PMMA. Applying and drying an adhesive containing a copolymer containing polyethylene and MMA or a copolymer containing polypropylene and MMA; removing the spacer on the jaw model in the first flask;
The first flask and the second flask are made of an olefinic thermoplastic elastomer containing at least polyethylene or polypropylene as a hard segment, or a mixture of the olefinic thermoplastic elastomer and a thermoplastic elastomer consisting of a styrene-ethylene-butylene copolymer. A process of sandwiching the lining material made of the material in a softened or molten state and pressing the flasks together.

(B) Complete denture Figure 1 shows an example of the case where it is adopted as a mandibular complete denture 1. In the figure, 2 is the denture base body made of PMMA resin, and 3 is the surface of the denture base body 2 facing the alveolar ridge mucosal surface. Approximately 0.5fi on the entire surface
Rubber elastic lining materials 4, 4, . Here, the following materials are used for the lining material 3 and its adhesive.

(b) Backing material As the lining material 3 material, an olefinic thermoplastic elastomer containing at least polyethylene or polypropylene as a hard segment, or a mixed material of this olefinic thermoplastic elastomer and a thermoplastic elastomer consisting of a 5EBS copolymer is used. Ru. The olefinic thermoplastic elastomer consists of a hard segment made of polyethylene or polypropylene and a soft segment made of a homopolymer or copolymer of butene, propylene, butadiene, etc., and has a softening temperature of 100°C or less, and a JIS standard.
It has a wide range of hardness (hereinafter simply referred to as hardness) from about 20 to 90. As this type of olefin thermoplastic elastomer, Tafmer (registered trademark) manufactured by Mitsui Petrochemicals Co., Ltd. is suitable. This thermoplastic elastomer is an α-olefin thermoplastic elastomer, and there are those that contain either polyethylene or polypropylene alone as a hard segment, and those that contain both polyethylene and polypropylene, and their hardness is as follows:
From about 20 to over 90. By blending these, the hardness can be adjusted within the usable range of about 40 to 80.

Since the olefinic thermoplastic elastomer begins to soften at around 70°C, a thermoplastic elastomer made of a 5EBS copolymer is blended with the olefinic thermoplastic elastomer to improve its temperature characteristics. Furthermore, the 5EBS thermoplastic elastomer has better shape retention against temperature changes than the olefin thermoplastic elastomer, so by mixing the two, the overall durability is improved. This kind of 5EBS thermoplastic elastomer is obtained by hydrogenating a styrene-butadiene thermoplastic elastomer, and for example, Lavalon (registered trademark) manufactured by Mitsubishi Oil & Chemical Co., Ltd. can be used. Figure 2 shows olefinic thermoplastic elastomer and 5EBS.
The hardness-temperature characteristics are shown when the mixing ratio of the thermoplastic elastomer is changed. In the figure, the numerator indicates the proportion of the olefin thermoplastic elastomer, and the denominator indicates the proportion of the SE and BS thermoplastic elastomers. As is clear from the figure, 5
It can be seen that increasing the mixing ratio of the EBS thermoplastic elastomer suppresses softening from around 70°C. In addition, if the hardness of the 5EBS thermoplastic elastomer is different,
Since the hardness changes due to mixing, the hardness can be adjusted by this. However, since increasing the amount of the 5EBS thermoplastic elastomer reduces the adhesive strength to the denture base body, the mixing ratio actually needs to be about 75% or less.

As mentioned above, the olefin thermoplastic elastomer itself begins to soften rapidly at around 70°C, but since most of the lining material is located between the denture base body and the alveolar ridge mucosal surface and is shielded from the outside, this softens at around 70°C. It is not heated to around 70℃, and the temperature around the lining material that is exposed in the oral cavity may reach that temperature momentarily, but the temperature is maintained to the extent that it softens and deforms. will not be done,
For practical purposes, a single olefinic thermoplastic elastomer may be used.

The molding temperature of the lining material 3 can be about 70° C. or higher. Therefore, it can be heated in hot water, steam, higher alcohol, or edible oil. In particular, since edible oil can be heated to about 200° C., the fluidity of the lining material 3 is further improved when heated to such a temperature. Therefore, it is also possible to put it in a tube or the like to make it into a lump and heat it.

The hardness of the lining material 3 is preferably at least two types, hard and soft, depending on the location of use, and the hardness may be about 70, and the softness may be about 50.

(c) Adhesive The adhesive for bonding the backing material 3 to the denture base main body 2 made of PMMA contains at least a copolymer containing polyethylene and MMA or a copolymer containing polypropylene and MMA. One manufacturing method will be described in detail below.

Polyethylene was heated and dissolved in toluene in a polymerization reactor, a predetermined amount of MMA and benzoyl peroxide (hereinafter referred to as BPO) as a radical polymerization initiator were added, and graft polymerization was performed at 70° C. in a nitrogen atmosphere. After polymerization for 4 hours, the polymer solution was poured into a large amount of poor solvent (methanol in this example) to precipitate and separate the polymer. Separation of PMMA and MMA monomers was performed using a Soxhlet extractor with ethyl acetate. Extraction was performed for 8 hours to dissolve and remove PMMA and MMA. As a result of analyzing the graft copolymer thus produced using infrared spectroscopy and other analytical methods,
It was confirmed that the desired molecular structure was obtained.

The following table shows three types of polyethylene-MMA graft copolymer products A with varying BPO concentrations.

It shows the degree of polymerization, degree of grafting, and grafting efficiency of B and C.

In Table 1, the unit of BPO concentration is X 10 mol/1, and the degree of grafting and grafting efficiency are values calculated using the following formula.

The graft copolymer obtained as described above was subjected to 1.1
．． 1. ) It was dissolved in dichloroethane to make a liquid adhesive.

1, 1.1. used as a solvent. ) Lichloroethane is
It is suitable as this type of solvent because it is non-toxic and has a boiling point of 74.1°C, which evaporates easily. In addition, chloride-based organic solvents such as chloroform, toluene, xylene, ethers, etc. can be used as the solvent.

FIG. 3 shows the results of analysis of copolymer product B using a differential thermal analysis needle. The melting point of copolymer product B was thereby determined to be approximately 118°C. This means that adhesive made of copolymer product B can be applied to the backing material to form a mochi-like PMM.
This means that when A is pressure-welded and polymerized and solidified by heating to about 100°C to 130°C, the above-mentioned copolymer product melts, thereby generating an adhesive function and improving its action. Guessed. In fact, it has been confirmed that when the bonding time is increased, the bonding function occurs even at about 100° C. due to a relaxation phenomenon.

Polypropylene was used instead of polyethylene, and MMA was added to it under the same conditions as in the polymerization method described above (conditions for product B).
A good adhesive was also obtained when a graft copolymer of polypropylene and MMA was produced by dissolving it in a solvent consisting of ortho-xylene.

Furthermore, the above-mentioned TAFMER (registered trademark) A4085 (product number), which is an olefin-based thermoplastic elastomer, was used as a backbone polymer and subjected to the same polymerization method as described above (product B).
graft polymerization of MMA under the following conditions) to produce a copolymer of α-olefin thermoplastic elastomer and MMA,
An adhesive can also be prepared by dissolving this in a solvent consisting of L, 1.1 trichloroethane.

The graft copolymers of polyethylene and MMA and graft copolymers of polypropylene and MMA were used as adhesive materials because of their compatibility with the polyethylene or polypropylene contained in the olefinic thermoplastic elastomer and their compatibility with the PMMA denture base. This takes compatibility into consideration. Therefore, the above-mentioned copolymer is not limited to a copolymer of polyethylene or polypropylene and MMAO, but may also be a terpolymer of polyethylene or polypropylene and MMA, or a copolymer of polyethylene or polypropylene with another substance such as vinyl acetate. MMA may be further copolymerized with the copolymer.

(d) Method for manufacturing a denture base FIG. 4 shows a method for manufacturing a denture base using the lining material and adhesive according to the present invention in the order of steps, and will be explained below in accordance with the figures.

(A) A jaw model 5 obtained by taking an impression from a patient is formed using plaster 7 in a first flask 6. A predetermined hardening plastic material such as a dental slow polymerization resin, a photopolymerization resin material, a thermosetting resin material such as plastic clay is applied to the lining material formation site on the jaw model 5 (the entire surface of the complete denture shown in FIG. 1). thickness,
For example, a spacer 8 of about 1 fi is formed. Since this spacer 8 corresponds to the part on which the lining material will be formed later, it is treated, for example, by making the surface in contact with the thin part of the gum thicker. This spacer 8 is molded while it is in a plastic state and then hardened.

(B) Wax 9 is heaped up in the shape of a denture base on jaw model 5 including spacers 8, and artificial teeth 4 are arranged on this. Such work is usually performed by a dentist.

(C) Cut off the peripheral portion of the denture base formed with wax 9 over a predetermined width. Since a lining material will ultimately be formed in this cut portion 10.10, the above-mentioned cutting process is performed while taking into account the portion that is preferable to be used as a lining material.

(D) The cut portion 10 of the wax 9 is filled with the same material as the spacer 8, such as thermosetting plastic clay.

This filling part is made thicker in order to make a clear boundary with the denture base body.

Subsequently, plaster 11 is placed around the filled portion of the spacer 8.
．． 11 is poured to fix the spacer 8.

(E) After applying a separating agent to the surface of the plaster mold of the first flask 6, the second flask 12 is placed on top of this, and the plaster 13 in a fluid state is poured into it.

(F) After the plaster 13 has solidified, the first and second flasks 6.12 are placed in a stacked state in a container 14 and immersed in a vortex at about 100° C. for about 5 minutes. This melts the wax 9 and simultaneously hardens the spacer 8.

(G) The pair of positive rollers 12 are divided and the wax 9 is removed by washing with hot water.

(H) A flexible release film 15.15 such as a polyethylene film is placed on the surface of each plaster mold of the flask 6.12, and a plastic material 16 such as clay is filled in the denture base space between the films 15.15. Ru. The plastic material 16 must at least maintain its shape after molding.

(I) The flask 6.12 is clamped and the plastic material 16 is molded into a shape that matches the denture base body.

(J) Flask 6.12 was divided and molded plastic material 1
6 placed on it, turn the flask 12 upside down, apply two-component silicone rubber to the surface of the plastic material 16, harden it, and apply approximately I.
A rubber layer 17 having a thickness of n to 2 mm is formed. Subsequently, another flask 18 is placed on top of the flask 12, and gypsum 19 in a fluid state is poured into it. The rubber layer 17 is later used as a mold when molding the denture base body.
When an undercut exists in the denture base body, the elasticity of the rubber layer 17 facilitates its removal.

(K) After the plaster 19 has hardened, the flask 12.18 is divided and the plasticizer 16 is removed together with the release film 15.15.

(L) Mochi-like PM formed by adding a polymerization initiator to liquid MMA monomer and kneading PMMA powder in the denture base space 20
Fill with MA21.

(M) Clamp the flask 12.18, put it in the container 22, place it in water vapor at about 100°C to 130°C, and
The denture base body 2 is formed by polymerizing and hardening MMA.

(N) Divide the flasks 12 and 18, apply adhesive 23 to the exposed surface of the denture base body 2, and dry.

Remove the spacer 8 from the flask 6 in step (1).

(0) The recess of the denture base main body 2 is filled with the lining material 3 by heating and softening at a temperature of about 120°C. This temperature needs to satisfy both the molding temperature of the lining material 3 and the softening temperature of the adhesive 23.

(P) Then clamp the flask 6.12. For filling the lining material 3, a press molding method or an injection molding method can be used. However, since the molding temperature of the lining material 3 can be approximately 120° C., it can be heated and molded in a vortex, steam, or edible oil, thereby eliminating the need for a special press molding machine or injection molding machine.

(Q) After cooling the flask 6.12, divide it, break the plaster, and take out the denture 24. Thereafter, the lining material 3 is subjected to processing such as grinding and correction, and the denture base body 2 is polished and the denture 24 is polished.
is completed.

Note that in the above steps, if the jaw model 5 does not have an undercut, steps (H) to J) can be omitted. That is, the spacer 8 is left in the plaster mold of the flask 6 in step (G), and this is used as the denture base body mold.

(e) Partial Dentures and Attachments The above-described manufacturing method is also useful for manufacturing partial dentures or dentures with attachments.

5(A) and 5(B) show a partial denture 25, in which the lining material 3 has protrusions 26.26 at both ends, and these protrusions 26.26 under the adjacent natural teeth etc. retaining teeth 27.27. It comes into contact with the cut and acts to maintain the denture. 28 is the alveolar ridge.

FIG. 6 shows an example in which the stand attachment 29 is used, 30 is a metal stud fixed to the tooth root 31, 3 is a lining material, and the attachment female 32 is used when molding the lining material 3. formed at the same time. 33 is a gingival part.

FIG. 7 shows an example of the attachment 34, in which 35 is a metal mail fixed to the retaining teeth 27. 3 is a lining material, and a female 36 which holds the mail 35 therebetween is integrally molded with the lining material 3 at the same time. A metal ring 37 fixed to the artificial tooth 4 extends from the female 36, and the male 35 engages with this metal ring 37. Reference numeral 26 denotes two protrusions formed on the lining material 3 so as to abut the undercuts of the maintenance teeth 27 from the left and right sides of the attachment 34.

<Effect of the invention> According to the present invention, the following effects can be obtained.

■As the lining material, an olefinic thermoplastic elastomer containing at least polyethylene or polypropylene as a hard segment, or a mixed material of this olefinic thermoplastic elastomer and a thermoplastic elastomer consisting of a styrene-ethylene-butylene copolymer is used, and adhesive is used. By using an adhesive containing at least a copolymer containing polyethylene and MMA or a copolymer containing polypropylene and MMA as an agent, the lining material can be firmly bonded to the denture base body made of PMMA. .

■The lining material softens at a temperature of about 70°C or higher, and the adhesive also softens at a temperature of about 100°C or higher, so it can be molded and bonded by heating in hot water, steam, or edible oil. becomes. Therefore, a lining material of any shape can be easily produced without using a special machine.

- Since the hardness of the lining material can be set arbitrarily, it can be set to the optimum hardness for each case, and the problems of being too hard or too soft, which have been seen in conventional commercially available products, are solved. In other words, lining materials having partially different hardnesses can be used depending on the operating characteristics in the oral cavity. At this time, the interface between materials of different hardness is completely integrated and continuous. In addition, when replenishing and correcting, if the lining material is softened and the same material is softened and pressure-welded to it, the two can be easily welded, so the correction can be carried out arbitrarily.

■As a thermoplastic elastomer containing at least polyethylene or polypropylene is used as a hard segment as the lining material, the properties of polyethylene or polypropylene provide appropriate wettability to saliva, resistance to oral bacteria contamination and erosion, and food coloring. It is possible to take advantage of the difficulty of dyeing due to the like, and improve the properties as a lining material.

■The rubber elasticity of the lining material does not change permanently and it is firmly bonded to the denture base body, so it can maintain a stable attachment function with strong suction even after long-term use.

■Since the lining material can be formed into any shape, it can be used not only as a lining material for complete dentures, but also to form the female of attachments such as Dalboa attachments and stud attachments in one piece and at the same time. becomes. Since the above-mentioned female supports and fixes the male part using the rubber-like elasticity of the lining material, there is no risk of its supporting function decreasing, and on the contrary, it absorbs the impact applied to the denture, reducing the burden on the alveolar ridge. be able to.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a denture base according to an embodiment of the present invention, and FIG. 2 shows an olefinic thermoplastic elastomer and 5EBS.
Figure 3 shows the hardness-temperature characteristic curve when the mixing ratio of the thermoplastic elastomer is changed;
) or Q) are cross-sectional views showing the manufacturing method according to the embodiments of the present invention in order of steps, and FIG. 5(A) is a top view showing one shape of a partial denture that can be manufactured by the same manufacturing method.
FIG. 5(B) is a sectional view taken along line II in FIG. 5(A), FIG. 6 is a sectional view showing another shape, and FIG. 7 is a sectional view showing still another shape.

Claims (1)

[Claims] (1) Form a spacer with a shape that matches the lining material on the plaster jaw model in the first flask, apply wax to the shape of the denture base body on the spacer, and arrange the artificial teeth on the wax. Step; A step of stacking a second flask on the first flask and filling it with fluidized gypsum and solidifying it; A step of dividing the pair of flasks and removing only the wax; The first flask or this A rice cake-like polymethyl methacrylate obtained by kneading polymethyl methacrylate powder into liquid methyl methacrylate monomer is sandwiched between a third flask having the same jaw model and the above-mentioned second flask, heated, pressed, and polymerized. Step; Divide the pair of flasks and contain at least a copolymer containing polyethylene and methyl methacrylate or a copolymer containing polypropylene and methyl methacrylate on a predetermined exposed surface of the denture base body formed by polymerizing and curing the polymethyl methacrylate. a step of applying and drying an adhesive; removing the spacer on the jaw model in the first flask, and bonding the first flask and the second flask to an olefin-based adhesive containing at least polyethylene or polypropylene as a hard segment; Including the step of sandwiching a lining material made of a thermoplastic elastomer or a mixed material of the olefinic thermoplastic elastomer and a thermoplastic elastomer made of a styrene-ethylene-butylene copolymer in a softened or molten state and compressing both flasks. Method for manufacturing denture base with elastic lining material